Transformer



May 2, 1939. A. E. RITTENHOUSE TRANSFORMER Filed Aug. 14, 1937 Arthur E, R1 fienhouse INVENTOR ATTORNEY.

Patented May 2, 1939 UNITED STATES PATENT o1=1=1cs rmnsroamna York Application August 14, 1937, Serial No. 159,126

3 Claims This invention relates to a transformer, with more particular reference to the type of structure that is adapted for use in the operation of large bells, chimes, valves, relays, damper con- 5 trols and similar units, and has for its object to provide an eflicient and practical device of this character that can be economically manufactured and will operate safely under the varying conditions to which it may be subjected.

In a more particular aspect, the invention has for its purpose to afford a transformer that will not overheat when subjected to an overload or a short circuit of the secondary, at a much lower cost of manufacture than the high reactance type 15 of transformer in use at present for this purpose.

Another object of the invention is to provide a transformer, economical to manufacture and having a capacity that enables it to be used with various units for which high reactance trans- 20 formers have heretofore been designed, and which is controlled through a thermostatic switch that automatically opens the primary circuit in case of overload or short circuit in the secondary circuit. i

25 It is also an object of this invention to provide a transformer that will not have the objectionable operating characteristics of high reactance transformers.

A further'purpose of the invention is to afford 30 an economical and practical design for readily supporting a thermostatic switch inoperative relation'ship between the laminations and housing of a transformer of this type, permitting ready assembly of the parts.

To these and other ends, the invention consists in the construction and arrangement of parts that will appear clearly from the following description when read in conjunction with the accompanying drawing, the novel features being 40 pointed out in the claims following the specification.

In the'drawing:

Fig. 1 is a perspective view of a transformer constructed in accordance with one embodiment 45 of the invention;

Fig. 2 is a plan view with the'top plate and clamping band removed; r

Fig. 3 is a perspective view of the clamping band,and

50 Fig. 4 is aside elevation, showing the housing in section.

Heretofore, the maximum capacity of a transformer of normal reactance that would operate within a safe temperature and with-an input not 55 to exceed fifty watts under any conditions, in-

eluding a continuous short circuit of the-secondary terminals, has been approximately five watts, and consequently, the general practice in building transformers for large bells, chimes and similar units requiring greater capacity than five 5 watts has been to design a transformer with a high reactance which limits the current in event of short circuit.

Such a high reactance transformer is relatively costly to manufacture because of the necessity of a larger core and generally larger design, and from an operating standpoint, such a transformer has less satisfactory regulation and lower efficiency. The reactance may be increased by enlarging the space between the primary and 5 secondary coils to increase the leakage flux, but this alsoincreases the cost of'manufacture and reduces the efliciency of the unit. This invention is designed to overcome these objectionable characteristics of a high reactance transformer, and to produce a'transformer costing little more than a normal reactance transformer, and yet operating as, safely and more efficiently than the high reactance type.

Referring more particularly to the drawing in which like reference characters refer to the same parts throughout the several views, I designates the usual laminations of a transformer, 2 and 3 are the conductors of the primary circuit, and l are the terminals of the secondary circuit. Conductor 3 extends to the primary coil, while conductor 2 of the primary circuit is connected to a terminal 5 of a thermostatic bimetallic switch 6 which is engageable with a contact I that is connected to a terminal 8 from which a connection 9 leads to'the other end of the primary cell.

.The thermostatic switch 6 is mounted upon a supporting plate lo'made of any suitable insulating material which is preferably removably positioned edgewise and held between opposite 40 ends ll of a generally U-shaped metal retaining plate that is positioned edgewise as shown. The opposite ends I I of the metal retaining plate may be provided with suitable pockets I! that receive the ends of the insulating support H! on which the thermostatic switch is mounted. The U- shaped retaining plate, designated generally at It, and the insulating support III, are both positioned edgewise as shown in Fig. 4, and are 1 clamped between the laminated section I and the adjacent portion, of the housing, as will now be described. 3

'Ihe housing includes opposite plates l4 and I! provided with parallel horizontal edge flanges It, while l'l designate outwardly turned attaching 66 flanges for securing the transformer to any suitable support. The plates l4 and [5 are held in operative relation with the metal retaining member I3 and the thermostatic switch support or other relatively large units, and in the event of overload or short circuit of the secondary terminals,'-the excessive heat generated will cause the bimetallic switch to move away from the contact 1 and open the primary circuit which remains open until the trouble has been corrected or the temperature lowered to a safe point.

With this construction, a transformer 01 nor.- mal reactance can be safely employed, andthe cost of manufacture is consequently much less than the high reactance transformers used heretofore. Also its operating efliciency and other characteristics are superior to those of the high reactance transformer.

The invention is not confined to the particular construction and arrangement disclosed, and this application is intended to cover any other adaptations that may come within the purposes of the invention or the scope of thev following claims.

I claim:

1. A transformer including a housing, a gen erally U-shaped retaining plate positioned edgewise within the housing, a support of insulating material arranged between the opposite ends of said retaining plate, a thermostatic switch carried by said support, and a primary circuit connected to the terminals of said .thermostatic switch. 2. A transformer including laminations, a housing consisting of opposite spaced plates, a clamping band located between and connected to said plates to retain them in position, a. generally U-shaped metal retaining plate arranged edgewise between said laminations and one of said plates, the opposed ends of said retaining plate having pockets 'formed therein, supporting plate of insulating material positioned edgewise in said pockets and extending between the opposed ends of the retaining plate, a thermostatic switch carried by. said insulating plate, and a primary circuit connected to the terminals of said thermostatic switch.

3. A transformer including laminations, a housing comprising opposite spaced plates having parallel edge flanges and outwardly turned attaching flanges, a clamping band having flanges which overlie said parallel flanges of the plates and end portions which extend between said outwardly turned flanges and are attached toeach other, a generally U-shaped metal retaining plate positioned edgewise between said laminations and the adjacent of said plates, a supporting plate of insulating material removably held edgewise between the ends of said retaining plate, a thermostatic switch carried by said supporting plate, and a primary circuit connected to the terminals of said thermostatic switch.

, ARTHUR E. RITTENHOUSE. 

